Horsetail-leaved casuarines
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Horsetail-leaved casuarines ( Casuarina equisetifolia ), branches with inflorescences |
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The horsetail-leaved casuarine ( Casuarina equisetifolia ), also known as the kangaroo tree or casuarina tree, is a species of the casuarina family (Casuarinaceae).
description
Vegetative characteristics
The horsetail-leaved casuarine is a slender, loosely crowned, evergreen tree that grows up to 6 to 35, rarely up to 60 meters. The bark is light grayish-brown to blackish. In its growth form and its foliage, it is reminiscent of a conifer . The greyish-green, needle-shaped branches are thrown off. As is typical for the casuarina family, the leaves have receded into tiny, pointed scales and seven to eight of them stand together in whorls .
Generative characteristics
Casuarina equisetifolia is dioecious ( dioecious ) or monoecious ( monoecious ) sexually separated. The unisexual flowers are greatly reduced. Bracts are absent; they are replaced by two bracts. The male flowers stand together in terminal, woody, small, cone-shaped, simple, spike-like inflorescences with a diameter of up to 12 millimeters and a length of 7 to 40 millimeters; they only consist of a stamen . The small (10 to 24 × 9 to 13 millimeters), cylindrical, cone-shaped to spherical, spiked inflorescences with the female flowers, which have red stigmas, are on the side short shoots . When ripe, the cone-shaped fruit stands lignify. They contain gray to yellow-brown, 6 to 8 millimeters long, winged nuts (Samara).
The number of chromosomes is 2n = 18.
distribution
The natural distribution area of the horsetail casuarina stretches from the northeast and north of Australia over the Pacific islands to the coastal regions of the tropical southeast Asia .
The horsetail casuarine grows naturally on beaches and can also cope with locations that are exposed on headlands. In places the tree forms large stands. The fruits are buoyant, which explains the large range of this tree species.
The horsetail casuarine is now common in the entire tropical belt, especially on beaches.
Others
The casuarine is planted because of its salt resistance and its rapid growth in many tropical and subtropical countries as an ornamental tree, for wind protection and for fortifying dunes . Their ability to grow even on very nutrient-poor sand is based on a. on a symbiosis with nitrogen-fixing bacteria (actinomycetes) of the genus Frankia (similar to the native sea buckthorn ), the so-called actinorrhiza .
The casuarina can develop proteoid roots .
Because of its hardness, the wood is one of the so-called "iron woods". Traditionally, this wood was used by Polynesians to build canoes and make maces .
Systematics
The first publication of Casuarina equisetifolia was done by Carl von Linné .
There are two subspecies of Casuarina equisetifolia :
- Casuarina equisetifolia L. subsp. equisetifolia
- Casuarina equisetifolia subsp. incana (Benth.) LASJohnson : She stays smaller. It occurs only in eastern Australia, New Caledonia and Vanuatu .
photos
Male and female inflorescences
Female inflorescences and fruit clusters
Fruit heads
Trunk and branches
swell
- Information on the species ( Memento of July 31, 2012 in the Internet Archive ) at the World Agroforestry Center . (engl.)
- Description in the Flora of Australia . ( Memento of March 26, 2005 in the Internet Archive )
Individual evidence
- ↑ Casuarina equisetifolia at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ Rafaël Govaerts (ed.): Casuarina. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved April 13, 2020.
